Safety device for steam-boilers.



No. 660,358.' Patented Oct. 23, I900.

J. H. BULLARD. I

SAFETY DEVICE FOR STEAM BOILERS.

(Application filed Feb. 8, 1900.) (N o M 0 d e I 5 3 My 5 3 A) 15 H /0 ML l 2/ UNlTED STATES PATENT ()FFICE.

JAMES H. BULLARD, on SPRINGFIELD, MASSACHUSETTS.

SAFETY DEVICE Foe STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 660,358. dated October 23, 1900.

7 Appli i n d February Serial No. 3,872. \llo model.) i

To all whom it may concern:

Be it known that I, JAMES H. .BULLARD, a citizen of the United States of America, residing at Springfield, iu the county of Hampden.

and State of Massachusetts, have invented new and useful Improvements in Safety Devices for Steam-Boilers, of which the following is a specification.

This invention relates to steam-boilers, and.

has special reference to such boilers as use liquid or gaseous fuel, the object of the invention being to provide means for shutting off the supply of fuel it for any reason the supply of water in the boiler is reduced to a point beyond which its continued evaporation would be unsafe; and the invention consists in a device adapted to close a valve in the pipe through which the liquid or gaseous fuel is supplied to the burner of the boiler when the water in the latter reaches acertain pre-' 3 is the combustion-chamber between the burner and the bottom of the biler,into which the pipe 4 enters. This pipe extends from the fuel-tank 5 to and through the combustion-chamber, wherein it is subjected to the heat of the burner and the liquid hydrocarbon therein vaporized. This pipe upon its exit from the combustion-chamber enters the body of the burner, into which it discharges its vapor or gas. This connection is not shown, as the construction is well known.

The liquid hydrocarbon in the tank 5 is forced through the pipe 4 by air stored under pressure in the upper portion of the tank and Supplied thereto by suitable mechanism through the pipe 6. Located in the pipe 6 is a valve 7, whereby the passage through said pipe may he closed. Said valve may be of any type, that shown in Fig. 1 (a globe-valve) being the one preferred. The stem of this fvalve is provided with a pinion 8, secured thereto, with which a rack 9 engages, said rack being attached to a piston-head 10 by its inner end and being held axially true with' said piston-head by the flanged guide-roll 11 and by its engagement with the teeth of the pinion 8. Said piston-head has a sliding .movement in the cylinder 12, the lower end of which may be open, if desired, and. the upper end of which is connected by pipe 13 with the boiler at a point a short distance above the bottom thereof. The precise point 'at which this pipe 13 is connected with the .boiler is immaterial, butit will always be the .point below which the water in the .boilercan- .not be lowered by evaporation or otherwise without causing the fuel-supply to be cut off. In the drawings the point selected for this connection of the pipe 13 with the boiler is through the bottom support of the gage-glass, (indicated by 14.) This entrance to the boiler through this supp ort is equivalent, of course, to the entrance thereof directly into the shell of the boiler. The gage-glass isindicated by 15 (and ordinarily the connection with the boiler will be made at this point) and its upper support by 16. To provide for the actuation of the valve 7 at the proper time through themovementof the piston-head 10, a disk 17, of fusible. metal, is located between the end of the pipe 13, where it enters said support 14, and the column of water in said support. Said disk is of such a composition that the temperature of live steam will cause the disk to melt, and thus open a clear passage from the boiler into the pipe 13, through which the boiler-pressure may act on the piston-head 10 to force it from the upper end of its cylinder (the position in which it is shown in the drawings) to the lower end thereof, thus closing the valve in the fuel-pipe 4. The fusible disk may be secured in said support in any suitable way, whereby it may be in position to normally close the passage 18 through the boss 19 on said support from the interior of the latter to the pipe 13. In practice this passage is made smaller than the area of the disk, as shown in the drawings, to the end that it may dissipate the heat as rapidly as possible that is taken up from the water, for the difierence in the temperatures of the water and steam is relatively slight, and thus the disk is always near its melting-point when there is steam in the boiler, and it is thus desirable to keep the temperature of the disk as low as possible. This may be eifected also by securing the disk in the pipe 13 by increasing the distance between the disk and the boiler beyond that shown in the drawings.

In the drawings the disk 17 is shown secured in the support 14:, as follows: The boss 19 is screw-threaded, and a union couplingnut 20, engaging the end of the pipe 13, is screwed onto said boss, clamping the fusible disk 17 between the end of said boss and the.

flanged end of the pipe. In this construction the end of the passage 18 is of practically the same diameter as that of the interior of the pipe 13 and will register with it, and when the water in the boiler reaches a point where the passage 18 will be uncovered, so that steam may come in contact with the disk 17, the central portion of the latter will be melted, thus opening a clear passage through the pipe 13 to the cylinder and efiecting the closing of the valve 7 by the pressure in the boiler, as described.

The construction shown in Fig. 2 merely illustrates a type of gate-valve which may be used instead of the globe-valve shown in Fig. 1. In this construction, Fig. 2, the rack and pinion for operating the valve are replaced by a stem 21, whose lower extremity is shaped into a gate to close the passages through the pipe 13 by the descent of said gate, actuated by the action of the boiler-pressure against the piston-head 10, as in Fig. 1. Fig. 1, however, illustrates the preferred construction, for it is desirable that the valve 7 in the pipe 5 remain tightly closed until a new fusible disk has been placed in the support 14; to close the passage 18, and this is better accomplished by the use of the globe-valve or some similar valve than by the construction shown in Fig. 2.

To insert a new disk, it is only necessary to unscrew the union-coupling and swing the end of the pipe 13 to one side, insert the disk,

and replace the coupling. The rack 9 may be forced upward before the union-coupling is screwed down tight, whereby the pipe 13 may be vented.

In the construction shown in Fig. 2 it would be necessary to unscrew the pipe 13 from the top of the cylinder 12 to raise the piston and open the valve. I

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is-

1. The combination with a steam-boiler, a gas or hydrocarbon burner therefor, and a source of supply for the latter, of a pipe from said source to said burner, a valve in said pipe, valve-operating mechanism actuated by the boiler-pressure, a passage through the shell of the boiler below the'normal waterlevel therein leading to'said mechanism, and means for closing said passage consisting of a piece of metal fusible by contact of steam therewith, but normally protected from such contact by the immersion of a part thereof in the water of the boiler, substantially as described.

2. A steam-boiler and a gas or liquid fuel burner therefor, a source of fuel-supply for the latter, a pipe from said source to the burner, a valve in said pipe, and means for closing said valve consisting of a cylinder, a pipe therefrom entering the boiler below the water-level, a piece of metal fusible in the presence of steam normally closing the passage in said pipe, and normally protected from contact with steam by the water of the boiler, a piston in the cylinder adapted to be operated by the boiler-pressure, and a connection between said piston and said valve whereby the movements of the piston in opposite directions will close and open the valve, substantially as described.

JAMES H. BULLARD.

Witnesses:

K. I. CLEMoNs, H. A. CHAPIN. 

